1. Field of the Invention
This invention relates to cement block handling machines and more particularly to an apparatus for simultaneously off-loading a plurality of blocks from a pallet carried on a first conveyor and depositing them on a second conveyor, with the apparatus having two distinctive operating modes.
2. Description of the Prior Art
Devices for removing cementitious blocks from a pallet carried on a first conveyor and transferring them to a second conveyor have long been used in cement block manufacturing plants. Usually, these prior art devices simply push the blocks off of the pallet onto the second conveyor and in many instances this type of transferral is very satisfactory. However, in other instances it is desirable to turn the blocks over during the transferral and in still other instances such turnover is mandatory.
By way of explanation, some types of cementitious blocks, such as those often referred to as cap blocks, simple pushing of that type is perfectly satisfactory in that orientation of these blocks is unimportant as far as subsequent plant handling, shipping, job site handling and craftsmen preferences are concerned.
Cementitious blocks of the type which are used in conjunction with mortar for erecting building walls and the like, currently are the largest single type of cementitious block manufactured. Although not absolutely necessary, it is desirable that these mortar bonded blocks be turned over during the above described transferrral operation in that skilled craftsmen who lay the blocks prefer to have the smoothest side facing up which facilitates their task. When the blocks are fabricated, the smothest surface of the block is formed by the pallet and therefor to comply with craftsmen preferences, the blocks must either be turned over at the plant or on the job site. Turning the blocks at the manufacturing plant is much easier in that machinery can be employed to accomplish the task whereas job site turning of the blocks is a manual operation.
The high cost of labor has recently prompted searches for interlocking cementitious blocks which are self-aligning and can be bonded by an adhesive rather than mortar, and blocks of this type are now appearing in the marketplace. A particular block of this type is fully disclosed in a U.S. Patent Application entitled: INTERLOCKING CEMENTITIOUS BUILDING BLOCKS, Ser. No. 799,725, Filed on May 23, 1977, now U.S. Pat. No. 4,107,894, by the same inventor. Briefly, this block is formed with an array of recesses on one surface and an identical array of projections on the opposite surface. The block is fabricated on a special pallet which, in addition to serving as a pallet, acts as a die for forming the array of projections. This special combination of pallet and die is fully disclosed in U.S. Pat. No. 3,998,423, issued Dec. 21, 1976 to the same inventor and entitled: COMBINATION DIE AND PALLET. Since the array of projections of this particular type of block are formed by the special die and pallet, those projections face downwardly and the blocks must be inverted upon removal from the pallet to prevent breakage, and so that the blocks can be stacked in cubes for shipping purposes.
The known prior art devices for removing blocks from a pallet and transferring them from one conveyor to another are single function devices. That is, a first general type of mechanism is employed to push the blocks from the pallet onto the second conveyor, and a second general type of device will accomplish the removal and transfer with a turnover mechanism. To the best of my knowledge, no single apparatus has been devised or suggested which is selectively operable to accomplish both types of removal and transfer motions.
Since the prior art block removal and transfer mechanisms are single function devices, manufacturing plants must provide two separate block removal and transfer stations, i.e., one station equipped with a push-off mechanism and another station equipped with a turnover mechanism. A two station system is costly as it requires extra conveyors, power lines and the like, and occupies twice as much space as would otherwise be needed. An alternative to the two station system is one which requires time consuming equipment relocation when switching from the production of one type of block to another.
In addition to the above problems associated with the prior art single function devices, the block turnover mechanisms known to me are large cumbersome machines which are designed to invert one block at a time which produces problems with production schedules.
Therefore, a need exists for a new and improved selectively operable multi-operational mode apparatus for simultaneously removing a plurality of cementitious blocks from a pallet on a first conveyor and transferring them to another conveyor, with this apparatus overcoming some of the problems and shortcomings of the prior art.